Summary / Abstract (Administrative Supplement) Consistent with the vision of the Translational Outcomes Project in Neurotrauma (TOPNT) (UG3/UH3) RFA, we assembled a multidisciplinary team and proposed to evaluate two complementary pathological mechanism- based TBI outcome measures ? (i) biofluid biomarker assessment, and (ii) MRI-neuroimaging biomarker assessment. The objective of this administrative supplement is to facilitate cross-site harmonization and validation of neuroimaging and biofluid-based biomarker methods across the 4 funded study centers. We have the following supplementary aims: Supplementary Aim A1: To develop and optimize a multiparametric MRI protocol that completely meets needs for all labs in the consortium and to determine cross-lab measurement reproducibility on MRI calibration phantoms, live healthy control rats, and ex vivo rat brains. Supplementary Aim B1- Subject purified rat, and/or mouse and human GFAP and their calpain and caspase-digest to different measurement assays using western blot, ELISA and mass spectrometry at the two UG3 TOP-NT biomarker lab (UCLA, and UF). Supplementary Aim B2- At both UF and UCLA sites, terminal animal biosamples (control, injured) will be examined with the above GFAP assay approaches.